The invention relates to a compression piston ring.
EP 2 206 909 A1 discloses a piston device for internal combustion engines, comprising a first and a second compression ring, wherein the second compression ring has a notch on the slot side. The running face may have a conical design.
A steel piston ring is disclosed in EP 1 413 806 A1, comprising a running face having a varying geometry contour, an inner circumferential surface, and an upper and a lower flank surface. The rounded transition region from the running face to the lower flank surface is provided with a recess having an approximately square or rounded contour.
It is known in general to provide upper and lower edges at the running faces, or rounded edges, on chrome-plated piston rings, which can prevent chipping of the wear-resistant layers.